379 
\ G7 

>y 1 



Issued May 10, 1912. 

U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF CHEMISTRY— BULLETIN No. 155. 

H. W. WILEY, Chief of Bureau. 



LARGE SCALE EXPERIMENTS ON THE 

PROCESSING OF JAPANESE 

PERSIMMONS; 

WITH NOTES ON 

THE PREPARATION OF DRIED PERSIMMONS. 



H. C. GORE, 

Assistant Chemist, Divinon of Foods. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



ORGANIZATION OF BljaEAU OF CHEMISTRY. 

R. E. DooLiTTLE, Acting Chief of Bureau. 
F. L. DuNLAP, Associate Chemist. 
W. D. BiGELOW, Assistant Chief of Bureau. 
F. B. Linton, Chief Clerk. 

J. G. Shibley, Supervisory Clerk, Interstate and Import Records. 
A. L. Pierce, Editor. 
A. E. Draper, Librarian. 
Division of Foods, W. D. Bigelow, Chief. 

Food Inspection Laboratory, L. 'M. Tolman, Chief. 

Food Techuoloj^y Laboratory, E. iL Chace, Chief, and Assistant Chief of Division. 

Oil, Fat, and Wax Laboratory, H. S. Bailey, Chief. 
Division of Drugs, L. F. Kebler, Chief. 

Drug Inspection Laboratory', G. W. Hoover, Chief. 

Synthetic Products Laboratory ,,W. O. Emery, Chief. 

Essential Oils Laboratoiy, E. K. Nelson, Chief. 

Pharmacological Laboratory, William Salant, Chief. 
Chief Food and Drug Inspector, W. G. Campbell. 
Miscellaneous Division, J. K. Haywood, Chief. 

Water Laboratory, W. W. Skinner, Chi<:f. 

Cattle-Food and Grain Laboratory, G. L. Bidwell, Acting. 

Insecticide and Fungicide Laboratory, C. C. McDonnell, Chief. 

Trade Wastes Laboratory, under Chief of Division. 
Contracts Laboratory, P. H. Walker, Chief. 
Dairy Laboratory, G. E. Patrick, Chief. 
Food Research Laboratory, M. E. Pennington, Chief. 
Leather and Paper Laboratory, F. P. Veitch, Chief. 
Microchemical Laboratory, B. J. Howard, Chief. 
Physical Chemistry Laboratory, C. S. Hudson, Chief. 
Sugar Laboratory, A. H. Bryan, Chief. 
Sections: 

Animal Physiological Chemistry, F. ('. Weber, in Charge. 

Bacteriological Chemistry, G. \V. Stiles, in Charge. 

Enological Chemistry, W. B. Alwood, in Charge. 

Nitrogen, T. C. Trescot, in Charge. 

Plant Physiological Chemistry, J. A. LeClerc, Chief. 

Food Technologist, A. W. Bitting. 
Food and Drug Inspection Laboratories: 

Boston, B. H. Smith, Chief. 

Buffalo, W. L. Dubois, Chief. 

Chicago, A. L. Winton, Chief. 

Cincinnati, B. R. Hart, Chief. 

Denver, R. S. Hiltner, Chief. 

Detroit, H. L. Schulz, Chief. 

Galveston, G. M. Bartlett, Acting. 

Honolulu, Hawaii, A. W. Hanson, Acting. 

Kansas City, Mo., F. W. Liepsner, Chief. 

Nashville, R. W. Balcom, Chief. 

New Orleans, W. J. McGee, Chief. 

New York, A. W. Ogden, Acting. 

Omaha, S. H. Ross, Chief. 

Philadeljjhia, C. S. Brinton, Chief. 

Pittsburgh, M. C. Albrech, Chief. 

Portland, Oreg., A. L. Knisely, Chief. 

St. Louis, D. B. BisBEE, Chief 

St. Paul, A. S. Mitchell, Chief. 

San Francisco, R. A. Gould, Chief. 

San Juan, P. R., A. E. Taylor, Acting. 

Savannah, W. ('. Burnet, Chief. 

Seattle, II. J\I. Loomis, Chiif. 



Issued May 10, 1912. 

U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF CHEMISTRY— BULLETIN No. 155. 

H. W. WILEY, Chief of Bureau. 



LARGE SCALE EXPERIMENTS ON THE 

PROCESSING OF JAPANESE 

PERSIMMONS; 



WITH NOTES ON 



THE PREPARATION OF DRIED PERSIMMONS. 



H."^ C. GORE, 

Assistant Chemist, Division of Foods. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



t-v 



c^^ 



._'s°- 



^"..^ 



LETTER OF TRANSMITTAL. 



k)X' 



U. S. Department of Agriculture, 

Bureau of Chemistry, 
Washington, D. C, March I4, 1912. 
Sir: I have the honor to submit for your approval an account of 
certain experiments which have been conducted during the past 
year by H. C. Gore, of this bureau, on the processing of Japanese 
persimmons on a large scale and on the preparation of the dried 
fruit. Mr. A. V. Stubenrauch, of the Bureau of Plant Industry, has 
cooperated with Mr. Gore throughout the course of the work, giving 
advice as to the general scope and conduct of the experiments. From 
the data herein recorded explicit directions for processing persim- 
mons on a large scale may be formulated and an idea obtained of the 
probable place that processing may hold in the persimmon industry. 
The preparation of dried persimmons on a laboratory scale indicates 
that a product of excellent quality may be obtained by the use of 
simple methods. 

I recommend that this manuscript be printed as Bulletin 155 of 
the Bureau of Chemistry. 

Respectfully, H. W. Wiley, 



Hon. James Wilson, 

Secretary of Agriculture. 



Chief of Bureau. 



n m 

iY20 1913 



CONTENTS, 



Pa^e. 

Introduction 5 

Apparatus and methods used in processing 5 

Experiments at Macclenny, Fla 9 

Experiments at Glen St. Mary, Fla 12 

Experiments at Washington, D. C 12 

Discussion of results 18 

Preparation of dried persimmons 19 

Summary 20 



ILLUSTRATIONS 



Fig. 1. Apparatus used in processing Japanese persimmons 7 

2. Rate of softening of processed and unprocessed Tane-nashi persimmons 

kept at different temperatures 15 

3. Rate of softening of processed and unprocessed Zengi persimmons kept 

at different temperatures 17 

3 



LARGE SCALE EXPERIMENTS ON THE PROCESSING OF 
lAPANESE PERSIMMONS; WITH NOTES ON THE PREPARA- 
TION OF DRIED PERSIMMONS. 



INTRODUCTION. 

During the seasons of 1907 to 1910, inclusive, experiments on 
Japanese persimmons were carried on in cooperation with Mr. Taylor 
and Mr. Fairchild, of the Bureau of Plant Industry.^ It was found 
that upon keeping the fruit for several days in an inert gas such as 
carbon dioxid it becomes nonastringent while remaining firm. Dur- 
ing the season of 1911 experiments on processing in carbon dioxid 
were extended to a semicommercial scale in order to determine the 
value of the method when applied to the commonly grown varieties 
of Japanese persimmons. 

In the experiments described herein, except when otherwise noted, 
the persimmons to be processed were placed in large containers of 
galvanized iron, which were then tightly closed. The air was then 
displaced by carbon dioxid. When the fruits had become non- 
astringent they were removed and kept under observation in com- 
parison with check lots consisting of unprocessed fruits of the same 
picking, to determine the effect of the treatment on their keeping 
and shipping qualities. Each variety so treated in Florida was sub- 
jected to a shipping test, while the persimmons processed by keeping 
in carbon dioxid at Washington were used in studies on keeping at 
different temperatures. 

APPARATUS AND METHODS USED IN PROCESSING. 

The apparatus used in processing is shown in figure 1. It con- 
sisted of tanks of galvanized iron (A), in which the fruit was 
processed on a large scale, glass desiccators (B), in which a few per- 
simmons could be treated at a time, and liquefied carbon dioxid in 
steel cylinders (C). Each of the galvanized iron boxes was 25 inches 
square and 24 inches high. It was large enough to hold four of the 
six-basket carriers commonly used in shipping persimmons. The 
upper edge and cover were so constructed that the box could be 
closed air-tight by means of clamps. This construction, shown in de- 
tail at (D), was designed by Mr. S. J. Dennis, of the Bureau of Plant 

» U. S. Dept. Agr., Bureau of Chemistry Bui. 141. 



6 PROCESSING OF JAPANESE PERSIMMONS. 

Industry, and proved entirely satisfactory. The cost per box, with 

accessories, was as follows: 

For box and cover |18. 00 

One dozen clamps 3. 00 

Three brass stopcocks, at 27 cents each 81 

One and one-fourth pounds of white rubber tubing, at 79 

cents a pound 1- 00 

Total 22. 81 

It is recognized, however, that some changes would be desirable 
if tanks for processing persimmons were to be made in quantity. In 
such a design the rims of the tanks and covers should be made of cast 
iron hmged together and fitted with eyebolts and slots. The adja- 
cent surfaces should be planed and a solid rubber gasket used. The 
design shown in figure 1 does not require special castings. 

In processing persimmons these tanks are filled with the fruit, 
which may be packed, if desired, in the standard six-basket carriers, 
and may or may not be wrapped. The cover is clamped in position, 
and the box tested for tightness by use of the water gauge (E). It 
should be entirely free from leaks on the bottom or sides, and so tight 
that the rate of equalization of small differences in pressure, indi- 
cated by the gauge, is slow. Carbon dioxid is then passed in through 
the lower stopcock, while the displaced air flows out at the upper 
stopcock on the opposite side. The water gauge is useful here in 
guarding against too high pressures, which might easily cause per- 
manent distortion in shape, or bursting. The flow of carbon dioxid 
is continued until the stream of displaced air tastes strongly of car- 
bon dioxid. After such a taste is noted, the flow is continued for a 
few mmutes longer; the stopcocks are then closed and the box left 
undisturbed for the time required in processing. 

The necessity of opening the tanks to ascertain the progress of the 
processing should be avoided by placing a few persimmons in process 
in smaller containers. The most convenient apparatus for this pur- 
pose is the tubulated glass desiccator of the pattern shown in (B), 
which may be obtained from dealers in scientific apparatus. It 
should be kept at the same temperature as that of the tanks, on 
account of the influence of temperature on the rate of processing. (See 
p. 14.) As showai in (B), it is fitted -svith a rubber stopper carrying 
necessary delivery tubes. These may be of glass, or preferably of 
copper or other metal. The stopper should be well lubricated before 
forcing it mto place, so that it will fit air-tight, and then be tied in 
position. The ground-glass surfaces must be plane. They are coated 
with vaseline. In displacing the air the carbon dioxid is passed in 
through the delivery tube, which reaches to the bottom of the desic- 
cator. It is well to fasten the cover in place with cord or small 
clamps, because increases in pressure in the desiccator occasioned by 
the formation of carbon dioxid in the fruit may cause it to pop off 



APPARATUS AND METHODS USED IN PROCESSING. 



suddenly. The fruits in the desiccator are examined from time to 
time to determine when processing is completed, taking care to close 
at once after opening and to renew the supply of carbon dioxid quickly. 
Carbon dioxid may be purchased from dealers in soda-water sup- 
plies in liquefied form in steel cylinders holding 10 or 20 pounds at 
about 10 cents per pound. This is equal to a cost of about 1.1 cents 




Fig. 1.— Apparatus used in processing Japanese persimmons. A. Tank of galvanized iron. B. Desic- 
cator. 0. Cylinder of liquefied carbon dioxid with reducing valve- D. Detail showing construc- 
tion of edges of the tank and cover. E. Water gauge. 

per cubic foot of the gas when expanded to atmospheric pressure. 
These cylinders of liquefied carbon dioxid are under very high pres- 
sure and must not be handled roughly ; neither is it safe to allow them 
to become heated by the direct rays of the sun. The reducing valve, 
which is shown attached to the cylinder in figure 1, is very useful in 
regulating the flow of carbon dioxid, and may usually be obtained of 



8 



PROCESSING OF JAPANESE PEESIMMONS. 



the dealer supplying the gas. If no reducmg valve is used, sudden 
stoppages will usually occur during the outflow due to the choking 
of the orifice in the needle valve with solid carbon dioxid. Such 
stoppage is usually followed by a sudden rush of gas, and very close 
watching is necessary if annoymg accidents are to be avoided. 

Processing experiments were conducted at the nurseries of the 
Griffiiig Bros. Co. at Macclenny, and at the Glen St. Mary nurseries 
at Glen St. Mary, using in all cases fruit freshly picked from the trees. 
Two of the iron tanks were used at each locality. At the outset it 
was supposed that the control of the humidity was an important 
feature in processing, and so the treatment of the persimmons was 
conducted in one of the tanks at each locality, with no attempt made 
to lessen the very humid conditions which occur during processing, 
while in the other the humidity was somewhat lessened by dis- 
tributing about 50 pounds of dry starch among the persimmons. 
Perceptible differences in the amounts of moisture which collected at 
the top of the boxes during the processing j^eriod were noticeable in 
the experiments at each locality, but as no injury traceable to exces- 
sive humidity was observed at any time, the measures taken to lessen 
it are without importance. 

The experiments in Florida were started September 19 and com- 
pleted September 27. During this period the diurnal changes in 
temperature were quite uniform, as shown by recording thermome- 
ters operated at each locality. The experiments at Macclenny were 
conducted in a carriage shed, the doors of which were usually kept 
closed. Here the temperature ranged from 70° to 86° F., with an 
average of about 77° F. At Glen St. Mary experinents were carried 
on in an open shed, and the temperature variation was from 73° to 
99° F., with an average of about 80° F. 

The number of fi'uits used in process and m check lots and the 
time required m processing are shown in Table I. 

Table I.^ — Tivie required in -processing different varieties of Japanese persimmons. 





Where processed. 


Date. 


Average 

temi»ra- 

ture. 


Number of fruits— 


Time re- 
quired in 
carbon 
dioxid. 


Variety. 


In 
process. 


In con- 
trol. 


Triumph 

Do 


Macclenny, Fla 


1911. 
Sept. 19-22... 
Sept. 22-24... 
Sept. 19-22... 
Sept. 19-26... 

Oct. 5-15 

Sept. 19-24... 
Sept. 19-26... 
Sept. 2(>-27... 

Oct. 7-19 

Sept. 2.5-27... 
Oct. 23-27.... 
Sept. 19-22... 

do 


"F. 

77 
77 
77 
77 
69 
77 

80 
69 
77 
69 
77 
77 
80 
69 


395 

196 

219 

144 

9 

49 

37 

431 

474 

447 

540 

3 

2 


118 

117 

100 

72 

9 

25 

18 

1200 

100 

253 

100 






Days. 
2i 


do 


li 


ImxJerial 


do 


4i 


Hachiya 


do 


7 


Do. 




10 


Okame 


Macclenny, Fla. 


^\ 


Tane-nashi 


do 


7 


Do 


Glen St. Mary, Fla 


7 


Do 




12 


Zenei 


Macclenny, Fla 


2 


Do 


Washington, D. C 


4 


Hyakume 


Macclenny, Fla 


li 


Yemon 


do . 


li 


Costa ta 


Glen St Marv Fla 


Sept. 20-24... 
Oct. 5-7 


4 


Taber's23... 


Washington D. C 


68 


71 


2 









Approximately. 



EXPERIMENTS AT MACCLENNY, FLA. 9 

The various lots of persimmons were quite evenly ripened and of 
the degree of maturity at which they are usually picked for ship- 
ment to northern markets, with the exception of Okame (see p. 10). 

EXPERIMENTS AT MACCLENNY, FLA. 

At Macclenny the following varieties were processed: Triumph, 
Imperial, Hachiya, Okame, Tane-nashi, Zengi, Hyakume, and Yemon. 
Triumph. — Two experiments were made with this variety. Two 
and one-half days and one and two-thirds days in carbon dioxid, 
respectively, were required before the persimmons were nonastrin- 
gent. In the first experiment 513 fruits were used, of which 395 
were processed, while 118 constituted the control. On the comple- 
tion of the processing all of the persimmons m the tanks, with the 
exception of one specimen which softened, were as hard as when 
placed in process. Of the control 90 were firm, and 28, or 24 per cent, 
were softening. Three days later the processed fruits were noticed 
to be rapidly deepening in color, many possessing the beautiful deep 
red shade characteristic of this variety when ripe. This color change 
distinguished them sharply from the check lots, which were still 
yellow. Several of the processed reddened fruits were tasted at 
this time in contrast with normally ripened specimens. The flavor 
of the former was slightly but distinctly less agreeable than that of 
the latter, the fruits lacking freshness. On the follo\ving day the 
firm persimmons of the experiment, both processed and controls, 
were packed in carriers and sent to Washington, D. C.,. by express. 
They arrived at the department promptly and were kept at about 
60° F. until they were examined on October 2. The processed fruits 
were found to have softened greatly and were utterly ruined for com- 
mercial purposes, but the controls, as a whole, were firm and in good 
condition. 

On September 22 a second lot of Triumph persimmons was placed 
in process at 6 o'clock p. m. These fruits were found to be non- 
astringent two days later at 10 a. m., an interval of 40 hours. The 
processed fruits showed the reddening conspicuously on September 
26 but had not softened. The firm fruits of the experiment were 
then sent to Washington in the same shipment with those of the 
first experiment. Upon inspection on October 2 the processed per- 
simmons were found to be in very poor condition, resembling closely 
the first lot of processed Triumph, though they were not so badly 
softened, whereas the controls were in excellent condition. 

From these two experiments it is evident that the variety processes 

readily in from 40 to 60 hours at Florida temperatures and that 

after removal from the carbon dioxid it may be kept for four days 

at these temperatures before deterioration, except a slight loss in 

37998°— Bull. 155—12 2 



10 PROCESSING OF JAPANESE PERSIMMONS. 

flavor, occurs. It would therefore be practicable to process this 
variety for local use, since it is no more perishable when removed 
from the carbon dioxid than are most small fruits or peaches. It is 
clearly shown, however, that processing greatly injures the naturally 
excellent carrying qualities of this variety. 

Imperial. — This variety resembles Costata in size and shape. A 
total period in carbon dioxid of four and one-half days was required. 
During keeping for two days after processing 24 per cent softened, 
while 8 per cent of the controls softened. The fu^m processed and 
control fruits were sent to Washmgton in the same shipment with 
Triumph. When examined, on October 2, the processed specimens 
were found to be softening, whUe the control fruit was in good con- 
dition. As in the case of Triumph, it is clear that while this variety 
may be processed for marketing locally it is not advisable to process 
with a view to shipping long distances. 

Ilachiya. — This fruit required seven days in which to become non- 
astringent. On sliipment to Washington all of the processed fruits 
softened, while the controls remamed firm. These softened speci- 
mens were delicious in eating quality when examined on October 2, 
although they were not quite so palatable as normally ripened fruits. 
The difference was at first noticeable only by careful comparison with 
softened specimens among the controls. The processed fruit rapidly 
lost in eating quality on keeping in the laboratory, the flesh darkening 
noticeably from day to day. It is evident that it is impracticable to 
[)rocess this variety except for local use. 

Olcame. — But relatively few of these fruits were available, and they 
were as a whole very unevenly ripened, the color ranging from green 
to orange yellow. Care was taken to mclude in the processed and 
control lots equal proportions of specimens of the different degrees of 
ripeness. They processed in four and one-half days. No difference 
in time of processing the fruits of different degrees of maturity was 
evident, the immature fruit becoming nonastringent about as rapidly 
as the more highly colored persimmons. During the two days' keep- 
ing at Florida temperatures follo^vulg the removal of the processed 
fruit from the container a large proportion (35 per cent) of the treated, 
fruit softened, while all of the control remained firm. On shipping 
to Washington all of the processed fruits had softened by October 
2, the controls remaining firm. In this case, therefore, as with the 
three varieties just mentioned, processing mjuros the shipping quality 
very seriously. 

Tane-nashi. — Seven days were required in carbon dioxid. During 
this period 56 per cent of the controls softened, while all of the speci- 
mens in process remained firm. The examination of the fruits at 
Washington on October 2 showed both processed and control fruits 
to be softening. No deterioration in flavor or color such as was 



EXPERIMENTS AT MACCLENNY, FLA. 



11 



noted in the case of Triumph and Hachiya occurred with the proc- 
essed fruits of the Tane-nashi variety. When soft the processed 
specimens could not be distinguished from those that had softened 
normally. 

Zengi. — Two groves of persimmons at the GrifFmg Bros.' nurs- 
eries at Macclenny bear fruit resembling Zengi but differing from it 
as ordinarily described in that most of the fruit is yellow-fleshed and 
seedless as well as much larger in size. It closely resembles in habit 
of tree, lateness, and size and shape the variety known as Taber's 
23, and indeed the fruits of the two varieties can not be distmguished. 

A large number of these Zengi persimmons were gathered and 
placed in process on September 25. Two days later the fruit was 
found to have become sweet. The processed specimens, together with 
the controls, were expressed to Washington, D. C, on September 27 
and were examined on October 2. In marked contrast to all the other 
lots experimented with in Florida, the processed fruit as well as the 
controls endured the shipment without softening. From this time 
on counts were made of the firm and softened fruits at intervals until 
October 20, when the fruit had dried out to such an extent that the 
counts became uncertain. The figures are shown in the following 
table: 

Table II. — Rate of softening of processed and unprocessed Zengi persimmons shipped 
to Washington from Macclenny and kept at a temperature of about 69° F. 



Date. 


Interval after 
picking. 


1 
Percentage of softened fruit. 


Processed (447 
specimens). 


Control (253 
specimens). 


1911. 
Oct. 7 


Days. 
13 
15 
19 

22 
24 
26 


28 
39 
46 
63 
69 
72 


30 
44 
50 
55 
57 
60 


9 


13 


16 


18 


20 ... 









It is evident that although processing perceptibly accelerates soft- 
ening, the effect is but slight and not apparent until 22 days after 
picking. The natural excellent shipping qualities of the variety 
were therefore uninjured. No deterioration in flavor or color occurred. 
Tlie processed persimmons were excellent in flavor at all times before 
and after softening. 

Hyakmne and Yemon. — But three and two specimens, respectively, 
of these varieties were available for study. They were processed m 
desiccators, becoming nonastringent in 36 hours. It is regretted that 
it was not possible to secure more specimens so as to determine the 
effect of processing on the rate of softening. Both varieties are of 
distinct promise in view of the fact that they become nonastringent 
veiT readily. 



12 



PROCESSING OF JAPANESE PERSIMMONS. 



EXPERIMENTS AT GLEN ST. MARY, FLA. 



At Glen St. Mary the processing tanks were filled on September 20 
with Costata and Tane-nashi. Costata required four days, wliile Tane- 
nashi processed slowly, requiring seven days before the fruit became 
edible. During this time at least one-third of the control Tane-naslii 
had softened. For several reasons an exact count of the controls was 
not made. The processed Costata and Tane-nashi were sent to 
Washington, D. C, by express on September 27, together with the 
fii-m specimens of their controls. The fruit was kept at about 60° F. 
after its arrival in Washington until October 3, when it was examined. 

Costata. — The processed fruits had softened much more than the 
controls and had darkened somewhat, so that they were hardly mar- 
ketable. The controls shipped successfully. 

Tane-nasTii. — The processed fruit was found to be in good condition 
on examination in Washington and the unprocessed fruit also stood 
the transportation excellently. In the following table are shown the 
percentages of softened fruits when first examined, and two and four 
da3's later. 

Table III. — Rate of softening of processed Tane-nashi 'persimmons shipped to Washing- 
ton after processing at Glen St. Mary and kept at a temperature of about 69° F. 



Date. 


Interval after 
picking. 


Percentage of softened fruit. 


Processed (431 
specimens). 


Control (125 
specimens). 


1911. 
Oct. 3 


Days. 
13 
15 

17 


38 
81 
99 


33 
57 

77 


5 . . 


7 





In this instance it will be noted that the processed fruit is not com- 
pared mth the original control, but with the fruits of the control which 
were firm on vSeptember 27. A distinct effect of the processing in 
hastening the rate of softening of the persimmons is evident. 

EXPERIMENTS AT WASHINGTON, D. C. 

Four varieties were processed at Washington. These were Hachiya 
and Taber's 23, from Mr. Macklin at Dinsmore, Fla. ; Zengi, from the 
Grifhng Bros. Co. at Macclenny; and Tane-naslii, from the Glen St. 
Mary Nurseries Co. 

Hachiya. — Eighteen large, evenly ripened fruits were received on 
October 5. Nine were placed in carbon dioxid in desiccators, while 
the remainder served as checks. Ten days were required for process- 
ing at an average laboratory temperature of about 69° F. Six days 
later all of the processed fruits were softening, while three of the con- 
trols still remained firm. The processed fruits gradually darkened 



EXPEEIMENTS AT WASHINGTON, D. C. 



13 



and lost flavor. Tliis result confirms the experience with Hachiya 
processed in Florida. 

Taber's 23. — This variety, wliich so greatly resembles the Zengi 
grown at Macclenny (see p. 11), was received on October 5. The fruits 
placed in carbon dioxid became nonastringent at laboratory tempera- 
tures averaging 69° F. m two days. All of the 68 fruits so processed 
remained firm, wliile of 71 control specimens 8, or 11 per cent, were 
softening at the end of the two days. The data on the subsequent 
rate of softening are given in the following table: 

Table IV. — Rate of softening of processed and unprocessed Taber's 23 persimmons. 



Date. 


Interval after 

placing in 
carbon dioxid. 


Percentage of softened fruit. 


Processed (68 
specimens). 


Control (71 
specimens). 


1911. 
Oct. 7 


Days. 

2 

9 
12 
20 
25 



25 
25 
45 
63 


11 

18 
34 
48 
63 


14 


17 


25. .. 


30 





The rate of softening is thus shown to be practically unaffected by 
the processmg. No darkenmg of the flesh or deterioration in flavor 
occurred at any time, either before or after softening. 

Tane-nashi. — A large shipment of Tane-nashi was received by 
express on October 7 and placed at once under observation. One 
carrier of fruit was held in the laboratoiy at a temperature averaging 
69° F., another was kept in a refrigerator at about 52° F., and a tliird 
was held in cold storage at 35° F. These average temperatures are 
estimated from the record sheets of thermometers kept beside the 
respective samples. These lots were used as controls of fruit which 
was processed at room temperature and then stored at these three 
temperatures. Four hundred and seventy-four persimmons were 
placed in process. These became nonastringent after an interval of 
12 days, and all remained firm except 17, or 4 per cent, which were 
softening from decay. During the same interval, of the controls at 
room temperature, 82 per cent became soft, and of the fruits held at 
refrigerator and cold-storage temperatures, 42 per cent and 6 per 
cent, respectively, softened. Three lots of 100 specimens each of 
the fii'm processed persimmons were selected for keeping at the three 
temperatures mentioned. All of the fruits were wrapped. The rates 
of softening of each of these three lots and their controls were deter- 
mined by counting at intervals. The results are shown in Table V 
and are given graphically in figure 2. 



14 



PROCESSING OF JAPANESE PERSIMMONS. 



Table V. — Rate of softening of processed and unprocessed Tane-nashi persimmons kept 
at three different temperatures. 



Interval. 


Room temperature. 


Refrigerator tempera- 
ture. 


Cold-storage tempera- 
ture. 


Processed 
(lOO).i 


Control 
(90). 


Processed 
(100). 


Control 
(88). 


Processed 
(100). 


Control 
(73). 


Days. 
12 


Per cent. 


Per cent. 
82 
91 
98 
99 
99 
100 


Per cent. 


Per cent. 
42 
61 
73 


Per cent. 


Per cent. 
6 
6 

7 


17 

23 

26 

30 

32 


78 
97 
99 
100 


4 
4 


4 
4 


10 


95 


5 


7 


38 




38 
67 
94 
100 


100 


6 

7 
7 

10 
16 
43 
03 


10 
15 
15 
16 
21 
26 
40 


44 






52 








59 








66 


















90 





















1 The total number of fruits used in each lot is given at the top of each column. 

The persimmons softened after removing from the process decidedly 
more rapidly at room temperature than did the controls. The refrig- 
erator temperature delayed the softening of the processed fruit 
markedl}^, but as soon as rapid softening began the rate was about 
the same as that of the control; the curves are practically parallel. 
In cold storage the processed fruit at first softened less and then more 
rapidly than the control. In no case was conspicuous injury to the 
fruit caused by the keeping in carbon dioxid. It must be kept in 
mind, however, that the data are incomplete, as studies on the 
behavior of the fruit on withdrawal from cool temperatures are lack- 
ing. Certain abnormalities, such as darkening of the flesh at bruised 
places and blackening of the flesh near the calyx, occurred after 29 
days in refrigerator storage, and it is probable that the persimmons 
would not have held up well if withdrawn at this time and kept under 
market conditions. The abnormalities were more frequent among 
the processed fruits than among the controls. The results of this 
experiment show that processing is fairly successful with this variety. 
The fact that a longer time was required for the persimmons to become 
nonastringent in Washington than in Florida is probably due to differ- 
ences in temperature. 

Zengi. — A large number of the yellow-fleshed Zengi were received 
late in the afternoon of October 23, and were placed in process on 
the following morning. About 1,100 fruits were received, and of these 
840 perfectly sound and firm specimens were selected for the experi- 
ments in processing. They were divided into several lots, the plan of 
the experiment behig identical with that just described for Tane-nashi. 
Three lots of 100 fruits each were placed in common, refrigerator, and 
cold storage, respectively, and the remainder placed in process at room 
temperatures. The average temperatures were practically the same as 



EXPERIMENTS AT WASHINGTON, D. C. 



15 




Si f^ 1^ S ^ S^ 

IS to "o V «^ «\i 



^~- 



16 



PROCESSIXG OF JAPANESE PERSIMMONS. 



in the preceding experiment with Tane-nashi. Four days were required 
in processing. All fruits but one remained firm, while of the controls at 
room temperature 16 per cent had softened. Three lots of 100 speci- 
mens each of the processed fruits were kept at the three temperatures 
and counts of all lots were made at intervals, all fruits being kept 
wrapped. The rate of softening of the various lots of persimmons 
is shown in Table VI and graphically in figure 3. 



Table VI. 



-Rate of softening after processing of Zengi persimmons kept at three different 
temperatures. 



Interval. 


Room temperature. 


Refrigerator tempera- 
ture. 


Cold-storage tempera- 
ture. 


Processed. 


Control. 


Processed. 


Control. 


Processed. 


Control. 


Days. 
4 


Per cent. 

2 
32 
66 
71 
84 
92 
100 


Per cent. 
16 
29 
48 
53 
63 
70 
73 
87 
92 
93 


Per cent. 


Per cent. 


Per cent. 


Per cent. 


6 





1 





1 


9 


13 


2 


2 





1 


15 . 


18 










21 


6 
17 


i-i 

33 






2 
2 


27 


29 


35 .. . 




91 
100 


64 
100 





2 
8 
17 
36 


2 
3 
7 

19 
36 
71 


42 




49 






60 .. 








73 








91 

















In many respects the curves resemble those obtained with Tane- 
nashi. The processing period, however, is very much shorter. The 
rate of softening of this variety was even better controlled by cooling 
to refrigerator temperature than in the case of Tane-nashi. The 
processed persimmons softened slightly more rapidly than the con- 
trols at room and refrigerator temperatures, respectively, but the 
differences are too small to be of practical importance. The processed 
fruit in cold storage softened somewhat less rapidly than the controls. 
No abnormalities among the firm or softened Zengi persimmons 
occurred on keeping either at room, refrigerator, or cold storage 
temperatures. 

Lots of from 6 to 12 specimens of the processed Zengi fruit were 
mailed on October 27 to 12 retail fruit dealers in various cities and to 
5 growers of persimmons in the South. Of the fruit dealers, 8 ex- 
pressed the opinion that a demand would have to be created for proc- 
essed fruit before it could be expected to sell. Only 3 commented on 
the excellent quality of the persimmons, while 2 expressed a preference 
for the normally softened fruit. On the whole, the comments of the 
fruit dealers were less favorable than was expected. This probably 
indicates that less difficulty is now being had in selling the astringent 
Japanese persimmons in their natural state than was the case a few 



EXPEKIMENTS AT WASHINGTON, D. C. 



17 




p: « "o ^ % 



18 PROCESSING OF JAPANESE PERSIMMONS. 

years ago. That the astringency of the Japanese persimmon will 
continue to retard greatly its wide introduction seems, however, 
probable. All of the 5 growers pronounced the samples of most 
excellent eating quality. 

DISCUSSION OF BESULTS. 

From the experiments just described some idea is given of the value 
of persimmon processing when applied to the varieties of Japanese 
persimmons commonly grown in this country. It can be recom- 
mended generally for treating the fruit for local distribution, as none 
of the varieties when processed were more perishable than are the 
small fruits or peaches. It can not be recommended, however, if the 
fruit is to be subsequently shipped for long distances except in the case 
of the seedless yellow-fleshed Zengi and Taber's 23, as the naturally 
fine shipping qualities of the persimmons are greatly injured. Zengi 
and Taber's 23 are not unfavorably affected. Possibly the fruit 
could be successfully shipped for long distances after precooling, as 
cool temperatures retard the rate of softening considerably, but this 
is a subject for further study. Processing may be successfully em- 
ployed after shipment, and it would seem to be particularly useful in 
so treating those varieties which, when ripened naturally, must 
become extremely soft before they are edible. The most conspicuous 
example of persimmons of this type is Hachiya, the most beautiful as 
well as one of the largest of all varieties. If placed in carbon dioxid 
when it is highly colored but firm it may be rendered nonastringent in 
a much shorter time than when the fruit is more immature, and when 
so processed is of most delicious eating quality. 

It is hoped that the ease by which the remarkable change in the 
fruit may be brought about will induce others to experiment with it, 
as it is probable that it must be repeatedly tried by a number before 
its place in the persimmon industry is definitely established. 

Col. Watrous^ in his report on persimmon processing by the Japa- 
nese method notes that it is expert work requiring skill and judgment; 
this is true also of processing in carbon dioxid. The maturity of the 
fruit and the temperature must be considered by the operator, while 
the time required in processing, the acceleration in rate of softening, 
and effect on flavor must be determined before it is possible properly 
to draw conclusions as to the application of the process to any par- 
ticular variety. The operator is especially cautioned not to use 
apparatus of a makeshift nature; for example, the employment of 
wooden containers for the fruit, which though apparently air-tight 
may allow diffusion of gases through the wood. The air must be 
displaced and kept away from the main lot of fruit in process for the 
time indicated by the small lots in the desiccators. If the air is not 

' U. S. Dept. Agr., Bureau of Chemistry Bui. 141, p. 6. 



PREPARATION OF DRIED PERSIMMONS. 19 

SO excluded delays in processing may be expected, while the fruit may 
soften rapidly both in process and afterwards and misleading results 
be obtained. 

A number of important varieties remain to be tested to determine 
how rapidly they become nonastringent when placed in carbon 
dioxid and the effect of the treatment on the rate of softening and on 
the flavor. Among these are Yemon, Hyakume, Taber's 129, and 
the newly introduced Chinese and Japanese varieties which are not 
yet fruiting in sufficient quantity for such experiments. 

PREPARATION OF DRIED PERSIMMONS. 

From time to time during the past few years persimmons have been 
dried in a steam-heated evaporator at the Bureau of Chemistry. 
Until the present season such experiments were purely of a prelimi- 
nary nature. It was developed, however, that certain precautions 
must be taken to insure satisfactory results. It was found necessary 
to peel before drying, as otherwise the skin becomes very tough and 
the shape of the fruit is distorted. It was desirable to peel and slice 
in such a way that the fruit is not stained by contact with iron knife 
blades, which quickly become coated with the blue-black iron-tannin 
salts. Nickel-plated knives were found useful. To secure the best 
appearance of the dried fruit it should be sliced at right angles to the 
axis, and spread on trays of galvanized or tinned wire netting m such 
a way that every part of each slice is weU aerated, as darkening 
occurs wherever the aeration is not sufficient. It was found best to 
dry at temperatures not exceeding 122° F. The variety Tane-nashi 
is most suitable for drying. It is of large size and the trees are pro- 
ductive. As there are no seeds circular disks showing the beautiful 
star-shaped centers can be cut easily and the fruit dries practically 
without change in color. 

A large quantity of Tane-nashi grown at Glen St. Mary, Fla., was 
dried at Washington, D. C, during the season of 1911, using the pre- 
cautions just mentioned. It became nonastringent soon after plac- 
ing in the drier. When removed, the dried slices were kept in a closed 
container for several days so that they became equalized in moisture 
content and were pliable. They were then pressed into small bricks 
and distributed to a number of persons interested in persimmons. 
The comment on the whole was very favorable. Many likened them 
to dried figs or dates. Samples have been kept under observation 
in the laboratory m tin boxes held in closed glass jars for three months. 
The color darkened slightly during this mterval, but the fruit remained 
perfectly sound and the flavor excellent. The drying of the seedless 
variety Tane-nashi is of much promise in view of the ease with which 
a very attractive product may be prepared. 



20 PROCESSING OP JAPANESE PERSIMMONS. 

SUMMARY. 

A method of processing persimmons on a large scale by keeping in 
carbon dioxid is described and an account is given of experiments in 
the application of the method to persimmons in Florida and at 
Washington, D. C. 

(1) All of the varieties tried became nonastringent when kept in 
carbon dioxid. The intervals in days necessary for processing at 
Florida temperatures are given in parentheses followmg the name of 
each variety: Triumph (If to 2^); Imperial (4^); Hachiya (7); 
Okame (4^); Tane-nashi (7); Zengi (2); Costata (4); Hyakume (H), 
and Yemon (1^). 

(2) All of these varieties were processed on a large scale in Florida 
and subjected to a shipping test with the exception of Hyakume and 
Yemon. With one exception (yellow-fleshed Zengi) processing 
greatly mjured the naturally excellent shipping qualities of the fruit. 
Tane-nashi was less seriously affected than many of the others. 
Zengi was practically unaffected in shipping quality by the treatment. 
Processing, therefore, can not be recommended for persimmons which 
are to be shipped long distances wdth the exception of Zengi and 
Taber's 23 (with which the yellow-lleshed Zengi is possibly identical), 
but it is ])racticable to process all of the varieties mentioned for 
marketing locally. 

(3) No undesirable effects were produced by high humidity while 
in process. 

(4) Processing in carbon dioxid at Washington required more time 
than in Florida, probably on account of the lower temperatures. 

(5) Keeping at refrigerator or cold storage temperatures consider- 
ably retarded the softening of the persimmons. 

(6) An excellent product in appearance and flavor was obtained 
by drying Tane-nashi persimmons. 



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